{"vulnerability": "CVE-2026-108586", "sightings": [{"uuid": "4df8e4ac-6252-41ec-9a2d-e9b6d4b25fd4", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2026-108586", "type": "seen", "source": "https://infosec.exchange/users/cve/statuses/117417559199624769", "content": "CVE-2026-108586 1MCP Agent 0.20.0 through 0.39.0 OAuth Tag-Scope Bypass via Negated Tag Filter 1MCP Agent (@1mcp/agent) 0.20.0 through 0.39.0 contains an incorrect authorization vulnerability that allows authenticated clients to bypass OAuth tag-scope enforcement using negated advanced tag-filter expressions. Attackers holding a single-tag token can send a filter like not <granted-tag> to list and invoke tools on backend MCP servers outside their granted scopes.\nhttps://www.cve.org/CVERecord?id=CVE-2026-108586https://hackmd.io/@haind/1mcp-negated-tag-filter-oauth-scope-bypasshttps://github.com/1mcp-app/agent/blob/v0.39.0/src/sdk/legacy/transport/http/middlewares/scopeAuthMiddleware.ts#L163-L183https://github.com/1mcp-app/agent/blob/v0.39.0/src/transport/http/routes/inspectHelpers.ts#L79-L102https://github.com/1mcp-app/agenthttps://www.vulncheck.com/advisories/1mcp-agent-0.20.0-through-0.39.0-oauth-tag-scope-bypass-via-negated-tag-filter#1mcp-app #@1mcp/agent#CVE_2026_108586#bot", "creation_timestamp": "2026-10-10T16:29:28.833768Z"}]}